Apparatus for resizing piston ring grooves



June 1934- H. F. PHILLIPS APPARATUS FOR RESIZING PISTON RING GROQVES Filed July 16, 1931 Patented June 26, 1934 APPARATUS FOR RESIZING PISTON RING GROOVES Harold Frederick Phillips, Belmont, Mass.

Application July 16, 1931, Serial No. 551,168

19 Claims.

the groove wider, and install a wider ring in the groove. This practice necessitates stocking a variety of over-width piston rings by a repair man to accommodate various types of pistons. It also necessitates rather careful machine work in enlarging the ring grooves.

It is an object of the present invention to resize the worn ring grooves of pistons to their original widths by forcing the material in the side Walls of the grooves into the grooves, so that rings having the same widths as those originally used can be installed in the grooves.

A further object of the invention is to restore the ring grooves to their original widths by a rolling process which is quickly and effectively performed.

Another object of the invention is the provision of a simple and effective machine for restoring the worn ring grooves of predetermined smaller widths.

A further object of the invention consists in reforming the ring groove to a predetermined smaller width by forcing material of the side waHs into the groove and then sizing the groove by expanding the groove to the desired width.'

.Another object of the invention consists in forcing the material in the side walls of the ring grooves into the ring grooves Without crowding the material against an abutment, and providing sizing rollers which roll in the ring groove that is being reformed and define the width thereof.

A yet further object of the invention is generally to improve upon methods and apparatus for resizing the worn ring grooves of pistons.

Fig. 1 is a plan view of a machine embodying the invention with a piston in operative position ,therein, the piston being shown in section through one of the ring grooves.

Fig. 2 is a side elevation of the machine of Fig. 1.

Fig. 3 is a sectional detail taken along line 33 of Fig. 1.

Fig. 4 is a sectional detail taken along line 4-4 of Fig. 1.

Fig. 5 is an enlarged sectional detail of one of the sizing rollers.

Fig. 6 is an enlarged sectional detail of a worn ring groove of a piston.

I Fig. '7 is a view similar to Fig. 4 but illustrating the resized ring groove.

An automobile piston 10 is usually provided With a plurality of ring grooves 12 in the head thereof. The ring groove in a new piston has parallel side Walls and is adapted to be but slightly greater in width than the width of the ring received therein. With extended use of the pls ton, however, the side walls become worn away as illustrated in Fig. 4. The outer. portions of the walls 14 usually are worn away more than the inner portions of the walls so that the ring groove becomes bell-shaped in cross section.

In accordance with the present invention, the material in the side walls of the groove is forced inwardly of the groove so that the ring is restored to its original width with the side Walls parallel. The machine for re-sizing the ring grooves comprises a base 16 which can be circular as here shown and has three upstanding, equiangularly spaced radially-extended integral bosses 18 which have radially extended rectangular grooves or ways 20 formed therein. The

grooves are coveredby cover plates 22 which are secured to the bosses by screws 24 andthe cover plates have ears 26 which depend downwardly over the outer faces of the blocks and the grooves therein. Slides 28 are located in said grooves and are movable radially inwardly and outwardly therein. Each slide comprises a spacer block 30 having top and bottom plates 32 and .34 fixed thereto and extended inwardly beyond the inner face of the boss where they carry a pin 36 which is removably secured in aligned apertures in said plates. The blocks can be forced inwardly toward a common center by means of pressure screws 38, 'WhlCh are screw-threaded into the ears 26 of the cover plates and bear against the outer ends of the slides. Each pin 1 carries a roller 40, 40a, or 40?), which has a hub -42 extended from one face thereof and rotatably supported on thepin, the axial length of the hub being such that the roller. is supported between the top and bottom plates of the slide without an 2 undue amount of axial play. A second roller 44 has a hub 46 which is journalled on the hub 42 of the first roller; and the axial length of the second roller and its hub is such that a considerable axial displacement of the roller is peri mitted whereby to adapt the roller for insertion in ring grooves or pistons having difierently axially-spaced grooves. The roller 40 is provided having parallel side walls 50. At the base of the flange 48, the roller is provided with peripherally continuous ledges 52 which are disposed on opposite sides of the flange 48 and have radial outer faces 54 and undercut peripheral faces 56 which merge with the radial faces 54 to provide continuous circular cutting edges 58.

The rollers 40a and 401) may be similarly constructed although they are preferably free from the cutting ledges and are as shown in Fig. 4.

In operation a piston 10 is inserted in the machine between the rollers and with the radial flanges of the rollers 40, 40a, and 40b located in the same groove and, as here shown, in the top groove of the piston and with the rollers 44 in the next adjacent ring groove. The slides are then forced toward each other by turning the pressure screws 38 in the proper direction until the outer cylindrical faces of the rollers 40a and 401) are seated upon the bottom faces of the ring groove and the cutting ledges 52 of the roller 40 bear upon the lands 60 and 62 on opposite sides of the ring groove to be re-sized. The piston is then rotated by any suitable means, preferably by a wrench, not shown, which is inserted in the piston and engages the wrist pin bosses. While the piston is being rotated the pressure screw 38 associated with the sizing roller 40 is turned to force the cutting ledges of the roller into the lands on opposite sides of the ring groove, the rotation of the piston and turning of the pressure screw being continued until the ring groove has been re-sized and restored to its desired size and shape. By this process the cutting ledges 52 combined with the undercut faces 56 thereof force the material in the lands inwardly of the ring groove, thereby reducing the width of the ring groove. The reduction in width of the groove takes place practically throughout the entire depth of the groove and is particularly pronounced at the outer portion, where the wear is greatest. The re-sized ring groove has the appearance illustrated in Fig. 7 wherein the walls 14a are straight and parallel with each other and circular grooves 64, formed by the cutting ledges, are present in the peripheries of the lands on opposite sides of the groove.

While the rollers 40a and 4017 can be identical in construction with the roller 40 it is preferred that the rolls 40a and 401) be free from the cutting ledges as illustrated in Fig. 4 and also be different from the roller 40 in certain respects. The ring groove preferably is somewhat wider than the width of the ring adapted to enter the groove. The flange 48 of the roller 40 is adapted to have a width between its parallel faces equal to the width of the ring. The rollers 40a and 40b are each adapted to have a width between their parallel faces equal to the width of the re-sized groove. Thus the roller 40 forces the material of the side walls of the groove in wardly until the inner faces thereof bear against the parallel side faces of the flange 48. The rollers 40a and 40b act to enlarge the re-formed groove by forcing back the material of the side walls and thereby sizing the groove to the width of the rollers and, at the same time, burnishing the opposed faces so that they are smooth and bright. The rollers 40a and 40b are thus sizing rollers while the roller 40 is a re-forming roll.

The upper rollers 44 have a width equal to the width of the re-sized groove and support the land 60 against being crowded into the second groove while the first groove is being re-sized.

After one groove has been re-sized, the piston is moved axially to enter the rollers in the next groove to be re-sized. In practice, the grooves are re-sized beginning with the groove furthest from the head of the piston and working toward the head so that the rollers 44 are located in re-sized grooves and hold them against deformation during the process of re-sizing an adjacent groove.

The pins 36 are removable from the slides so that rollers of various dimensions can be used to re-size grooves of various widths.

The above-described process of re-sizing ring grooves is applicable both to cast iron, aluminum and aluminum alloy pistons and, in general, to the various piston materials in present commercial use.

I claim:

1. Re-sizing apparatus for worn ring grooves of engine pistons comprising supporting means on which the piston is rotatable, a roller having a circumferential flange which enters the ring groove of the piston, said roller having a cutting ledge at one side of the flange which bears upon the piston land at one side of the groove and forces the material thereof into the groove, and means for advancing said roller and ledge toward the piston.

2. Re-sizing apparatus as defined in claim 1 wherein there are cutting ledges on opposite sides of the roller-flange which act on the piston lands on opposite sides of the ring groove and which force the material of both lands at the same time inwardly of the groove and toward the flange,

the flange limiting the inward movement of the land-material and defining the width of the groove.

3. Re-sizing apparatus as defined in claim 1 wherein the flange limits the inward movement of the land-material and defines the re-formed width of the groove and the character of the side wall thereof.

4. Re-sizing apparatus for the worn ring grooves of engine pistons comprising supporting means on which the piston is rotatable, a sizing roller having an outstanding sizing flange which enters the ring groove and a cutting ledge of smaller outside diameter than the outside diameter of said flange located at one side thereof adapted to bear upon the peripheral face of the piston land adjacent a side wall of the groove, said cutting ledge having an undercut periph eral face which exerts pressure on the land material in a direction to force the material inwardly of the groove and toward said sizing flange.

5. Re-sizing apparatus as defined in claim 4 wherein the sizing roller is provided with cutting ledges on opposite sides of the sizing flange and which exert equal pressures in opposite directions on the piston at opposite sides of the ring groove whereby to hold the sizing roller against undue tendency toward axial displacement.

6. Re-sizing apparatus for the worn ring grooves of engine pistons comprising supporting means on which the piston is rotatable, means acting on that part of a piston land adjacent a ring groove to force the material in one direction into said groove, and means for supporting the opposite side of the land to prevent the ma- 1 terial of the land from being displaced in the opposite direction into an adjacent ring groove.

7. Re-sizing apparatus for the ring grooves of engine pistons comprising supporting means onwhich the piston is rotatable, a re-sizing roller having means which acts on the piston lands opposite a ring groove toforce the material thereof into said groove, and a second roller which is located in an adjacent groove opposite the point where pressure is applied on the land between the groove to support the material of the land against displacement into the second groove.

8. Re-sizing apparatus as defined in claim 7 wherein the two rollers are concentrically and independently rotatable.

9. Re-sizing apparatus for the ring grooves of engine pistons comprising supporting means on which the piston is rotatable, a re-sizing roller having a circular flange which enters a ring groove and cutting ledges at the sides of the flange, a slide block movable toward and away from the piston having a pin on which said roller is rotatable, and a second roller rotatably supported on said first roller and having a flange positioned to enter a groove of the piston adjacent the groove in which the first roller is located.

10. Re-sizing apparatus for the ring grooves of engine pistons comprising supporting means on which the piston is rotatable, a slide block which is movable toward and away from the piston having a removable pin, a sizing roller having a hub journalled on said pin, said sizing roller adapted to enter a ring groove and force the material of the piston adjacent the wall of the groove into the groove, and a second roller loosely journalled on the hub of said first roller and axially displaceable thereon and positioned to enter an adjacent groove of the piston and hold it against deformation.

l1. Re-sizing apparatus for the ring grooves of engine pistons comprising a base, slides carried thereby and movable toward and away from a common center, and rollers journalled in said slides having flanges adapted to enter a common ring groove of the piston, and a rotary ledge associated with at least one of said rollers arranged to rotate on the periphery and to force the material of the piston land adjacent the ring groove inwardly of the groove.

12. Re-sz'zing apparatus for the ring grooves of engine pistons comprising a base, slides carried thereby and movable toward and away from a common center, rollers journalled in said slides having flanges adapted to enter a common ring groove of the piston, at least one of said rollers having means to force the material of the piston lands adjacent the ring groove inwardly of the groove, and other rollers located above and journalled concentrically with said first rollers and free for displacement in an axial direction and adapted to enter the next adjacent groove of the piston to hold the groove against deformation.

13. Re-sizing apparatus for the ring grooves of engine pistons including a forming roller having an outstanding flange which is adapted to enter the ring groove of a rotating piston and has a width equal to the width of the ring for the resized groove, said roller havin cutting ledges on opposite sides of said flange which force the material of the piston lands inwardly of the groove and toward said. flange, and a second roller having a flange which is adapted to enter the same ring groove and which has a width that is greater than the width of the flange of first roller and is adapted to force the side walls of the re-formed groove outwardly and thereby size the groove.

14. Re-sizing apparatus for the ring grooves of an engine piston comprising a base, slides movable thereon toward and away from a common center, rollers journalled in said slides having flanges adapted to enter a common ring groove, one of said rollers having a flange that is narrower in width than the width of the flanges of the other rollers and also having cutting ledges which force the material of the piston lands inwardly of the groove, and other rollers journalled concentrically with the first rollers and having flanges of the same width adapted to enter the next adjacent ring groove of the piston and support that groove against deformation.

15. Resizing apparatus for the worn ring grooves of engine pistons comprising supporting means for the pistons, a groove-sizing roller adapted to enter the worn ring groove having a predetermined thickness that is less than the width of the worn groove and a side face to which a wall of the groove is adapted to be conformed, a rotary ledge associated with said roller for forcing material of the land beside the groove inwardly of the groove and against the side face of said sizing roller.

16. Resizing apparatus for the worn ring grooves of engine pistons comprising supporting means for the pistons, a groove-sizing roller adapted to enter the worn ring groove having a predetermined thickness that is less than the width of the worn groove and side faces to which the walls of the groove are adapted to be conformed, and rotary ledges associated with said roller for forcing material of the lands on opposite sides of the groove simultaneously inwardly of the groove and against the opposite faces of said sizing roller.

17. Resizing apparatus for the worn ring grooves of engine pistons comprising means for supportinga piston rotatably, aresizing roller having a radial groove-sizing flange adapted to enter the ring groove and roll therein, said flange having a predetermined thickness that is less than the width of the worn groove, and means for rolling material of the lands beside the groove inwardly of the groove and against the sides of said groove-sizing flange as said piston rotates.

18. Resizing apparatus as defined in claim 17 having a slide that is movable toward and away from the piston and on which said resizing roller is rotatable, and screw means for advancing said slide toward said piston.

19. Re-sizing apparatus for the ring grooves of engine pistons including a forming roller having an outstanding flange which is adapted to enter the ring groove of a rotating piston, means providing rotatable cutting ledges which engage the piston land at a side of said flange and force land-material inwardly of the groove and against said flange, and a sizing roller having a flange which is adapted to enter the same ring groove and has a predetermined width that is greater than that of said first flange and is adapted to force the formed side wall of the groove outwardly and thereby size the reformed groove, said sec- 0nd flange being rotatable in frictional engagement with the side wall of the groove and thereby burnishing the side wall.

HAROLD FREDERICK PHILLIPS. 

